A nut is a type of fastener with a threaded hole that interfaces with a mating bolt. Bolts are a type of fastener with a threaded cylindrical barrel on one end of the fastener that mates with a complementary thread in the nut. The nut and mating bolt are kept together by a combination of thread friction, a slight stretch of the bolt, and compression of the parts. The most common shape for a nut fastener is hexagonal, because six sides give a good granularity of angles for a tool to approach from. However, the corners are vulnerable to being rounded off.
Nuts are traditionally removed using hand wrenches or screwdrivers by applying a counterclockwise rotational force to the head of the fastener. However, where the head of the fastener has been rounded, damaged or broken off through the application of excessive torque, or where the fastener has been corroded, it is very difficult and time consuming to remove the nut and bolt.
A further complication of nut removal using manual tools is that, where the nut is very large, such as those used in oil production, manual removal of such damaged nuts presents danger to the operator, or removal is impossible because of the degree of torque required for removal.
One type of device accomplishes nut removal by sawing off the nut, or by using a blow torch to cut the nut off of the bolt. However, these methods of nut removal result in damage to the nut and/or the bolt. This problem may be solved with devices which either drill the nut, or cut into the nut, so that torque can be applied to the nut for removal. However, these devices also result in further stripping and rounding of the nut.
Devices for the removal of large nuts using an air impact tool exist; however, in one such device, a cartridge having many small parts is used to apply torque to the damaged nut and these multiple small parts of the cartridge, such as multiple helical springs, studs and screws holding gripping jaws together are prone to breakage.
A further complication is that cartridges and other parts are held within a cylindrical housing a retaining ring or clip. The retaining ring or clip is prone to breakage, resulting in a damaged and useless tool.
Another complication of nut removal using a hand-powered tool is side loading, or the mechanical binding of threaded surfaces against each other. When side loading occurs, heat builds up due to friction between the threaded surfaces, creating a gall which is carried through the housing, tearing out the threads, and impeding nut removal.
Yet another complication is “chattering,” where the tool does not perfectly conform to the size of the fastener. When rotative force is applied using an air impact tool, the removing tool “chatters” over the damaged corners of the fastener, further stripping the fastener or damaging the tool interface with the fastener, and causing ‘radii’ to form on the end of the tool.
A further problem is presented with a single device for nut removal because the device is limited in the size of nuts which can be removed with a single tool; that is, different-sized nuts cannot be removed with the same tool because the nut heads cannot fit within the tool.
The use of a set of tools having a multiplicity of sizes to conform to different nut head sizes could solve problem of imperfect conformance between removal tool and nut size. However, regardless of the size, the result is chattering from an imperfect size conformance; thus, stripping of the nut thread occurs.
Further, the use of a set of tools having a multiplicity of sizes to conform to nut sizes presents another complication. If there exists a multiplicity of removal tool sizes in a set, the loss of one of the tools results in a useless tool set.
While the use of an air impact tool may remove much of the operator danger associated with hand wrenches, the use of an air impact tool presents a further problem. That is, the air impact tool, itself, creates a shock upon impact with the nut. When using sockets attached to air impact tools for nut removal, this shock impact can damage both the nut and adjacent surfaces, such as the rim of a tire that houses the nut attaching the tire to an axle on an automobile.
A further complication of some devices is that these ridged teeth on the gripping surface of the jaws which strip the nut heads having a set number of faces, i.e. a hexagonal nut head.
Another complication is the thickness of the housing of the socket containing the jaws of the nut removal tool. A housing which is too thick can cause damage to the fixture which the nut is screwed into, such as the rim of a tire. With the use of an impact wrench attached to a thick housing for the removal of such a nut, tire rims are frequently damaged during removal for tire mounting and balancing.
It would thus be desirable to have a nut removal tool that conforms to the size and shape of a multiplicity of nut heads, where the jaws of the tool comprise one piece, rather than a multiplicity of smaller pieces which can be easily lost or damaged, and where the jaws are retained within a thin housing through a shock-absorbing canted coil spring.